The invention relates to an apparatus as generically defined by the preamble to claim 1.
A preferred range of application of such apparatuses is the thickening of thin sludges, that is, the extraction of liquid from such thin sludges, so that a thick sludge discharge can then be provided at the outlet of the apparatus, with the dirty water and filtrate that occurs at the outlet of the process being carried away. Because of the conveyor belt, such an apparatus is as a rule called a xe2x80x9cbelt thickenerxe2x80x9d.
Until now it has been usual to have the individual method steps (addition of the polyelectrolyte for the flocculation, passage through a ripening path for the action of the polyelectrolyte, deposit onto the belt thickener, etc.) performed in separate structural units, which have to be coupled to one another more or less inconviently via pipelines and connecting parts, in order to assure a satisfactory sequence of these method steps.
These conventional embodiments also take up a great deal of space and are consequently inconvenient to realize for the final consumer; changes in the method sequence (for example if changes in the ripening times for different sludge consistencies are needed) can be made only with corresponding effort, and the same is naturally also true for inspections, maintenance and repairs.
It is therefore the object of the invention to make such an apparatus structurally simpler, easier to maintain and service, and more economical in terms of space.
According to the invention, this object is attained in accordance with the body of claim 1.
The fundamental concept of the invention is thus considered to be the common tub, which both statically-mechanically and functionally integrates the individual structural units and combines them in its method sequence.
The fundamental tub construction for all the essential functional components, and in particular the ripening time chamber and conveyor belt, also makes it possible to provide all the connections directly on the tub, for instance by means of suitable stubs or flanges, in particular in the lower region of the tub or directly on the underside of the tub, where these connections can be securely accommodated without requiring additional space and in a way protected from external influences.
The tub concept in particular makes it possible to solve problems in the region of the ripening time chamber in a novel way, either by inserting the entire ripening time chamber into the tub and fixing it there as a modular structural unit in a simple way, or by embodying the ripening time chamber of simple components, such as guide or deflector baffles which are then mounted and retained in their associated portion of the tub in a simple way, for instance in various positions, and can then optionally also be replaced again easily. Extreme ease of maintenance and repair is achieved by this concept, and in particular it is also possible to achieve the functional sequence of the method in a simple way by adapting the path length of the ripening time chamber by reorientation and/or replacement of suitable guide and deflector baffles, and thus to enable the apparatus of the invention to be converted for various kinds of mixtures of polyelectrolyte and sludge with different optimal ripening times.
Further advantageous features can be learned from further dependent claims.